试题与答案

在根尖的结构中,生长最快的部位是 A.成熟区 B.伸长区 C.分生区 D.根冠

题型:选择题

题目:

在根尖的结构中,生长最快的部位是

A.成熟区

B.伸长区

C.分生区

D.根冠

答案:

答案:B

题目分析:根尖是指从根的顶端到生有根毛的一段,它的结构从顶端依次是根冠、分生区、伸长区、成熟区。根冠位于根的顶端,属于保护组织,像一顶帽子似地套在外面,具有保护分生区;分生区被根冠包围着,属于分生组织,具有很强的分裂能力,能够不断分裂产生新细胞;伸长区在分生区上部,细胞逐渐停止分裂,开始迅速伸长,是根伸长最快的地方;成熟区也叫根毛区,在伸长区的上部,细胞停止伸长,并且开始分化,表皮一部分向外突起形成根毛,根吸收水分和无机盐的主要部位,成熟区及其上部,根内部分化形成导管,能输导水分和无机盐,故生长最快的地方是伸长区,故选B。

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题型:阅读理解

C

Elephants are the largest land animals and they need plenty of living span. They have seasonal migration(迁徙) routes. As human populations rise, elephant land is being cleared for agriculture and other kinds of development.

When animals are effectively trapped on small areas of land, it restricts the gene pool and also results in a shortage of food. Where elephant reserves (保护区 ) border agricultural areas, elephants are often attracted to leave parks to attack crops and barns. Only the strongest walls will stop an adult elephant, so farmers have great difficulty protecting their fields.

In India, elephants don’t only attack for food. Some even have developed a taste for rice beer. In Assam, elephant-human conflict has resulted in the death of more than 150 people and 200 elephants in two years.

Poverty leads to the killing of elephants for meat. If people don’t have enough food and their governments cannot afford to enforce poaching(偷猎) bans, it’s not difficult to predict the outcome.

Ivory comes from elephant tusks, which can grow to be 3 metres long. Both male and female African elephants have large tusks.

Most new ivory comes from Africa and is sold as a high status material in Asian countries such as Thailand, mainland China and Japan. It can fetch $150 a pound and is carved to make decorations, chopsticks and ink stamps(印章). The conservation priority(重点) here is to change public attitudes.

In some countries in southern Africa, where conservation efforts have been successful, there is not enough room for a growing elephant population and animals have to be killed. A CITES meeting in November 2002 ruled that Botswana, Namibia and South Africa may sell stock-piled(库存的) ivory, starting in 2004.

Many conservationists are convinced that this will fuel the demand for ivory and lead to more illegal poaching, they say it is almost impossible to tell legal from poached ivory. The governments argue that the sales will be used to fund conservation work.

64. Which of the following isn’t the result of smaller elephant land?

A. Seasonal migration.                        B. Elephant-human conflict.

C. Restricting the gene pool.                          D. Shortage of food.

65. The most important thing to protect elephants is _______.

A. to build strongest walls

B. to sell stock-piled ivory instead of illegal ivory

C. to enforce poaching bans

D. to change people’s ideas

66. What does the underlined word “this” in the last paragraph refer to?

A. The killing of dephants for meat.

B. The ban of the trade in African elephant ivory.

C. The selling of stock-piled ivory.

D. The sales to fund conservation work.

67. According to the passage, we can infer that_______.

A. farmers have trouble protecting their field since no walls can stop an adult elephant.

B. if the government could help solve poverty, there would be less killing of elephants.

C. only male elephants in Africa have tusks as long as 3 meters.

D. since there is not enough room for a growing elephant population, there is no need to ban poaching all over Africa.

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